Electromagnetic relays



Feb. 11, 1964 w. J. RICHERT 3,121,149

ELECTROMAGNETIC RELAYS Filed March 8, 1962 2 Sheets-Sheet 1 INVENTOR Walter J. Richert M Illlll IIHIIIIlI:

19 BY M w ATTORNEYS United States Patent O 3,121,149 ELEQTROMAGNETIC RELAYS Walter J. Richert, Princeton, Ind., assignor to American Machine & Foundry Co., a corporation of New Jersey Filed Mar. 8, 1962, Ser. No. 178,468 Claims. (Cl. 200-93) This invention relates to electromagnetic relays and, more particularly, to relays of that type in which the armature is retained in an actuated position by permanent magnet means.

Relays of this particular type have become known in the trade as magnetic latching relays. In the general type of relay to which the invention applies, a pivoted magnetic armature is actuatable by an electromagnetic motor selectively to two actuated positions, and permanent magnet means is provided to retain the armature in at least one of the actuated positions whenever that position is attained. Such relays may comprise two actuating clect-romagnets and a sing e permanent magnet, as disclosed in U.S. Patent 2,955,174, issued October 4, 1960, to Walter J. Richert, or may be made with only a single electromagnet, as disclosed in U.S. Patents 2,941,130, issued June 14, 1960 to Josef Fischer et al., and 2,960,583, issued November 15, 1960, to Richard T. Fisher et al.

For many applications for such relays particularly when the finished relay must be very small, it is highly desirable to employ only a single electromagnet, i.e., a single core equipped with one or more coils. However, because of the physical disposition of the single electromagnet, and the arrangements which are then possible for a permanent magnet, it has been difiicult to construct a single-electromagnet, permanent magnet latching relay in such a fashion that severe problems do not arise in both manufacture and operation of the relay. Assuming that the armature is made to extend generally parallel to the axis of the core of the electromagnet, it is then obviously d-iificult to find adequate space for the permanent magnet means to be provided for the latching tfunction. Similarly, if only a single permanent magnet is employed in such an arrangement, it is very difficult to find a satisfactory way to adjust pull in for the two actuated conditions of the relays, since shifting the permanent magnet in one direction, to increase the permanent magnet effect in one of the actuated positions, inherently decreases the permanent efiect in the other actuated position. Another problem which must be dealt with is that of establishing a flux path or paths of optimum effectiveness for the permanent magnet flux.

A general object of the invention is to devise a relay of the type described, involving only a single electromagnet as the actuating motor, which is free from the manufacturing and operational problems heretofore encountered with such relays.

Another object is to provide such a relay which is so constructed as to allow use of two independently installed permanent magnets for establishing the latching flux.

A tfiurther object is to provide a permanent magnet latched relay, employing only a single electromagnet to actuate the armature, wherein the permanent magnet latching eifect for each actuated condition of the relay can be adjusted independently.

Yet another object is to devise such a relay which is unusually compact, yet relatively easy to assemble and adjust.

A still further object is to provide such a relay wherein the permanent magnet flux is principally constrained to a path which does not include the core of the electromagnet.

In order that the manner in which these and other objects are attained in accordance with the invention can be understood in detail, reference is had to the accompanying drawings, which form a part of this specification, and wherein:

FIG. 1 is a side elevational view of a relay constructed in accordance with one particularly advantageous embodiment of the invention;

FIG. 2 is an end elevational view of the relay of FIG. 1;

'FIG. '3 is a top plan view of the relay of FIG. 1, with the contact header and armature removed;

FIG. 4 is a bottom plan view of the relay of FIG. 1;

FIG. 5 is a bottom plan view of the armature of the relay of FIG. 1; and I FIG. 6 is an exploded perspective view of the electromagnet and frame structure, including permanent magnets, employed in the relay of FIG. 1.

' Turning now to the drawings in detail, the embodiment of the invention there illustrated comprises an encased electromagnet, indicated generally at 1, a frame structure indicated generally at 2, FIG. 6, a pair of permanent magnets 3 and 4 carried by the frame structure, a pivoted armature 5, and a contact-and-terminal assembly 6. While those skilled in the art will understand that the relay is operative in any position, the position illustrated in FIGS. 1 and 2 is chosen as a normal position, with the electromagnet extending horizontally at the bottom and the assembly 6 at the top, in order to simplify description of the structure.

Considering FIGS. l, 2 and 6 particularly, it will be seen that frame structure 2 comprises a nonmagnetic metal support member 7 comprising a flat rectangular main body '8 and four upstanding legs 9-12, legs 9 and It being spaced apart along one long edge 13 of body 8 and legs 11 and 12' being spaced apart along the other long edge 14 of body 8. Two pole pieces 15 and 16 are employed, each rigidly secured to a diiferent end of body 8. The two pole pieces are identical and are formed of suitable magnetic material, such as soft iron. Pole piece 15 includes a fiat rectangular portion 17 which overlies the adjacent end portion of the upper face of body 8, being spot welded thereto at 18 and 19, FIG. 3. Depending at right angles from portion v17 is a flat portion 20 provided with a downwardly opening notch 21 having straight sides and a semi-circular bottom, notch 21 being centered below the longitudinal axis of body -8. Above notch 21, portion 20 is provided with two apertures through which extend two positioning tongues 22 integral with body 8.

The width of portion 17 is less than that of body 8, and one edge 23 of portion 20 extends, for part of its length, in the vertical plane containing the corresponding edge of portion 17, the remainder of edge 23 being offset toward notch 21, as seen in FIG. 2. On the other side of notch 21, portion 20 extend-s beyond the adjacent long edge 14 of body 8 and terminates in a straight edge 24.

From FIGS. 1, 3 and 6, it will be seen that pole piece 16 includes fiat rectangular portion 25 overlying the adjacent end portion of the upper face of body 8, being spot welded thereto at 2'6 and 27, FIG. 3, portion 25 being identical with portion 17 of pole piece 15. Depending at right angles from portion 25 is a flat portion 28 which is identical with portion 21} and includes a downwardly opening notch 29. Notch 29 is identical with notch 21, and the two notches are centered on a line spaced below body 8 and extending parallel to the longitudinal axis thereof. One edge 30' of portion 28 extends at first in a common vertical plane with the adjacent edge of portion 25 and is then oifset substantially toward notch 29, as seen in FIG. 6. On the opposite side of notch 29, portion 28 extends beyond adjacent edge '13 of body 8 and terminates in a straight edge 31.

I? a As will be seen, portions 17 and provide the pole faces for the actuating motor of the relay, the pole faces lying in a common plane parallel to body 8.

A yoke 32 of soft iron or other suitably magnetic material is fixedly attached to the central portion of body 3. Yoke 32 includes a fiat rectangular base 33 which extends across the upper face of body 8 and is fixed thereto by spot welding at 34, the upper face of base 33' lying in the same plane as do the pole faces presented by portions 17 and 2.5. Depending from opposite ends of base 33 are parallel legs 35 and 36. As best seen by comparing FIGS. 1 and 6, legs 35 and 36 are identical and are substantially thicker (transversely of the relay.) than is base 33, edges 13 and '14 of body 8 being notched to accommodate a portion of the thickness of the legs, as seen in FIG. 6. Longitudinally of the relay, legs 35 and 3d are each only one half as wide as is base 33. Each leg has one edge dis posed in a common plane with a long edge of base 33 and, as will be clear from FIGS. 1 and 4, the other edges of the legs lie in a plane which includes the center line of base 33. Outer side face 37 of leg 35 lies in a common plane with edge 31 of portion 28 of pole piece 16, while outer side face 38 of leg 36 lies in a common plane with edge 24 of portion 20 of pole piece 15.

Permanent bar magnet 3 is rectangular in side elevation and'in transverse cross-section and is disposed with one end engaged with the adjacent edge of leg 35 of yoke 32 and the other end engaged with the face of portion 28 of pole piece 16 which is directed toward electromagnet '1. Advantageously, magnet 3 is fixed rigidly in position by being soldered to pole piece 16. The upper long edge of magnet 3 extends in contact with the lower face of body 8 of support member 7. The outer side face of magnet 3 lies in a common planewith face 37 of leg 35 and edge 31 of pole piece portion 28.

Permanent bar magnet 4 is identical with magnet 3 and is disposed with one end engaged with the adjacent edge of leg 36 of yoke 32 and the other end engaged with the inwardly directed face of portion 20 of pole piece 1 5. The magnet is soldered to pole piece 15, extends in contact with the lower face of body 3 of member 7, and has its outer side face disposed in a common plane with face 33 of leg 36 and edge 24 of pole piece portion 20'.

It will thus be seen that the magnets 3 and 4, pole piece portions 23 and 28, and yoke legs 3-5 and 36 all depend from body 8 of support member '7 in respective planes which are at right angles to the plane of body 8, and are so arranged as to define sides and ends of an enclosure which accommodates electromagnet 1.

Electromagnet 1 is of the encased and potted type, comprising a casing of nonmagnetic sheet metal. The casing is in the form of a rectangular box consisting of a first portion which is drawn from a single sheet of metal and includes bottom wall 39*, FIG. 4, side walls =40 and 4d, and end walls 42 and 43. The open top of the box is closed by a fiat rectangular sheet 44 which has its edges soldered to the respective side and end walls. The core 45 of the electrom-agnet is in the form of a cylindrical rod of magnetic material of such length that the ends 46- and 47 thereof project beyond casing end Walls 42 and 43, respectively, the casing end walls 4 2 and 43, respectively, the casing end walls being provided with circular openings which accommodate and closely embrace the core.

While the distance between the outer faces of the end walls 42 and 43 of the casing for the electromagnet is materially less than the distance between the inner faces of pole piece portions 2i and 23', the length of core 45 is equal to the distance between the outer faces of pole piece portions 20 and 28. Hence, with the ends of the core projecting equally from the casing of the electromagnet, and with the casing centered between the two pole pieces, the end faces of the core 45 lie in the same planes as the outer faces of pole piece portions 23 and 28, respectively. The casing of the electromagnet is held in longitudinally centered position by magnetic washers 43 and 49 which snugly embrace core ends 46 and 47, respectively. Washer 4 8 is in face-to-face contact with pole piece portion 20 and casing end wall 42, while washer 49 is in face-to-face contact with pole piece por tion 23 and easing end wall d3. Hence, the washers assist in providing a good magnetic flux path between the core and the pole pieces.

End 46 of core 45 is seated in notch 21, while end 47 is seated in notch 29. The notches have a width equal to a the diameter of the core. ence, good magnetic engagement is assured between the core and the pole pieces.

A coil, or coils (not shown) are provided upon core 45 in conventional fashion, the coil or coils being preformed so that the core can be inserted therethrough and through the openings in casing end walls 42, 43. 'Before cover sheet 44 is installed, the casing is filled with a conventional epoxy resin or like insulating material which is cured to solid form after cover sheet 4-4 is soldered in place. The coil leads 50 and 51 are brought outthrough suit-able openings in side walls 46 and 41, respectively, of the casing, being sealed therein by glass beads or their equivalent.

From FiGS. l and 2 it will be seen that, when core ends 46 and 47 are properly disposed in notches 2.1 and 29, the casing is flat against the flat rectangular main body 8, casing side walls 4 3 and 41 extend only slightly below magnets 3 and 4, and leads 5t and 51 are convenient to the contact-and-terminal assembly 6. Advantageously, the openings for leads 5%) and 51 are so formed that the casing side walls are deformed outward ly cylindricaliy, as indicated at 53' and 51, respectively, in FIG. 2, the cylindrical projections embracing the glass beads for the coil leads.

From FIGS. 2 and 4, it will be seen that the spacing between yoke legs 35 and 36 is equal to the spacing between the outer faces of casing side walls 43 and 41. Accordingly, the cased electromagnet 1 is positively engaged between magnet 3 and leg 35, on the one hand, and magnet 4 and leg 36, on the other.

Base 33 of yoke 32 is providedwith an upwardly opening elongated groove 52, FIG. 3, which extends transversely of the relay, i.e., at right angles to the longitudinal axis of electromagnet 1. Armature 5 is a fiat, rectangular piece of magnetic metal provided at its center with a transversely extending groove in the bottom face of the armature, the groove extending completely across the armature. A magnetic bearing member 53, FIG. 5, of circular transverse cross section and equal in length to the width of armature 5, is seated in the groove in the bottom face of the armature and fixed to the armature, as by soldering or brazing. The groove in the armature is shallow enough to assure that a major portion of. the

cross-sectional diameter of bearing member 53 extends below the lower face of the armature, as seen in FIG. 1.

Armature 5 has a width distinctly less than the width of body 8 of support member 7. Groove 52 is centered on yoke base 32 and is slightly longer than is bearing member 53. Hence, when the exposed portion of member 53 is seated in groove 52, armature 5 is substantially centered relative to pole face portions 17 and 25 and electromagnet 1.

Assuming that permanent magnets 3 and 4 have their north poles adjacent yoke legs 35 and 36, respectively, and their south poles adjacent pole pieces 16 and 15, respectively, it will be seen that the yoke 32 will be mag netized, so that armature 5 is held in place, with member 53 engaged pivotally in groove 52, by the magnetic effort of the permanent magnet. Further, when the armature is pivoted to cause the corresponding end portion thereof to engage the pole face atforded'by portion 25 of pole piece 16, a good, close flux path is established for the flux of permanent magnet 3. This path comprises yoke leg 35, a portion of yoke base 33, hearing member 53, the corresponding half of armature 5, and pole piece 16. Similarly, when the armature is pivoted in the other enemas direction, to cause the other end portion thereof to engage the pole face afforded by portion 17 of pole piece 15, a closed path for the flux of magnet 4 is established. This path includes yoke leg 36, a portion of yoke base 33, bearing member 53, the corresponding half of armature 5, and pole piece 15.

When the electromagnet is energized, pole pieces 15 and 16 are magnetized, in a manner dependent upon the sense in which the electromagnet is energized to attract one end or the other of armature 5, causing the same to be pivoted into engagement with one or the other of the two pole faces, this mode of electromagnetic actuation being well known in the art. Assuming that the electromagnet has been energized in a sense causing the armature to pivot into engagement with the pole face afforded by portion 17 of pole piece 15, as illustrated in FIG. 1, permanent magnet 4 is then effective to latch the -arma ture magnetically in this actuated position, so that the armature is retained positively in the position seen in FIG. 1 after the electromagnet is deenergized and until the relay is actuated in the opposite sense. Conversely, when the electromagnet is so energized as to cause the armature to pivot in the opposite direction, into engagement with the pole face afforded by portion 25 of pole piece 16, permanent magnet 3 is then effective to latch the armature in that actuated position.

Assembly 6 carries both the stationary contacts and the movable contacts of the relay, as well as the corresponding terminal pins, and also acts as a closure for the case 54, FIG. 1 which houses the relay. The assembly includes a flat, relatively thick, rectangular header block 55 of suitable rigid insulating material. As will be clear from FIGS. 1 and 3, spaced notches are provided in the long sides of the header block to accommodate the tips of legs 9-12, the tips of the legs being cemented or otherwise suitably fixed to the header block. Each of legs 9-12 is offset below its tip, providing an upwardly facing shoulder which engages the lower surface of header block 55. The long sides of the header block lie in planes respectively containing the outer faces of legs 9, 10 and 11, 12..

Near one end, header block 55 is provided with a series of openings through which metal pins 56 extend, the pins being' fixed in place by the usual insulating seals. At its inner end, each pin 56 carries a stationary contact 57 which is formed from a strip of spring contact metal bent into the general form of a G, the tip of the pin 56 extending through suitable aligned openings in the base and cross-bar of the G, as shown in FIG. 1, and being soldered or otherwise fixedly attached thereto. The free end or top of the G constitutes the active portion of the contact and can be considered as being arcuate, the convex portion thereof facing armature 5. Pins 56 are aligned in a straight series which extends parallel to the adjacent end of header block 55, and contacts 57 are correspondingly aligned in a straight series.

Near the opposite end, header block 55 is provided with a series of openings through-which metal pins 58 extend, the pins being fixed in place by suitable seals. At its inner end, each pin 58 carries a stationary contact 59, contacts 57 and 59 being identical. As seen in FIG. 2, the free tip of each contact 57, 59* is slotted off-center to assure uniform engagement with the movable contacts and limit any tendency for the free portions of the fixed contacts to vibrate. From FIGS. 1 and 2, it will be seen that contacts 57 and 59 are arranged in two straight line series, each series being disposed above a different end portion of armature and the two series of contacts being spaced equally from and parallel to the pivoted axis of the armature. The free tips of all of the stationary contacts are spaced equally above the plane of pole piece portions 17, 25 by a distance materially greater than the excursion of the armature tips, so as to provide room for the movable contacts.

The movable contacts are provided by a plurality of arms 60 equal in number to stationary contacts 57. Each arm 69 is fixedly secured at its center to the tip of a different one of pins 51, the pins 61 being disposed in a straight series located midway between pins 56 and 58 and extending parallel to the two series formed by pins 56 and 58. Pins. -61 extend through openings in header block 55 and are fixed in those openings by the usual seals. Arms 69 are in the form of long, narrow, rectangular strips of thin spring metal bent to V shape with the apex of the V at the midpoint of the arm where the arm is attached to its pin 61. The Vs of the arms are inverted, so that the ends thereof slant downwardly and outwardly away from pins 61. Arms 61? are parallel, their ends being disposed in vertical alignment below the respective free tips of stationary contacts 57, 59. When arms 6d occupy their normal or relaxed positions, they are out of contact with the stationary contacts.

Located near one end of armature 5, and cemented or otherwise secured to the upper face thereof, is a pusher block 62 of insulating material. Similarly provided near the other end of the anmature is an identical pusher block 63. Blocks 52 and 63 extend parallel to the ends of the armature and, therefore, extend at right angles across the movable contact arms 6t As seen in FIG. 2, blocks 62 and 63 are of such length as to extend beneath all of the movable contact arms. The upper faces of blocks 62, and 53 are rounded tnansyersely of the blocks, as seen in FIG. '1. The angle of the V of movable contact arms 5% is sufficiently acute to assure that arms 61 will positively engage both blocks 62 and 63 in all operational positions of armature 5-. Thus, installation of assembly 6 causes arms at to be resiliently deformed to a V shape which is slightly less acute than for the normal, relaxed shape of the arms.

When armature 5 is actuated into engagement with portion 17 of pole piece '15, as shown in FIG. 1, the half portions of arms at nearest pole piece 16 are deformed upwardly and their tips engage the lower faces of the free tips of the respective ones of stationary contacts 55. Such engagement resiliently deforms. both the movable and stationary contacts, so that a resilient bias is established which opposes the latching action aiforded by permanent magnet 4 for this actuated position of the relay. When the armature is actuated in the other direction, coming into engagement with portion 25 of pole piece 16, the other half portions of arms 61) are deformed upwardly, their tips respectively engaging the lower faces of the free tips of stationary contacts 57. Such engagement resiliently deforms both the movable and the stationary contacts, establishing a spring force opposing the latching eifect of permanent magnet 3.

Header block 55 also carries pins 64, to which the coil leads are connected.

It will be understood that electromagnet 1 can include only a single coil, energizable sequentially with different polarity, or a pair of coils which can be connected in series or in parallel. A particular advantage of the invention is that it allows two coils energized from separate voltage sources and arranged for differential action, that is, in magnetic opposition to provide net magnetic flux representing the difference in levels of energiz-ation of the two coils.

Considering FIG. 6, it will be apparent that permanent magnets 3 and 4 are so arranged, relative to the balance of the relay structure, as to be readily accessible on an individual basis. It is thus convenient to accomplish pull in adjustments by individually changing the strength of the permanent magnets as required, this being accomplished by use of magnetizing and demagnetizing devices well known to those skilled in the art. It will also be apparent that the closed circuits established for the permanent magnet latching flux are such as to minimize loss of flux via the core of the electromagnet.

Considering FlGSqll and 4, it will be seen that, at each end of the relay, the end face of the core of the electromagnet, the outer face of the pole piece, and the corresponding edge of the header block all lie in a common plane, so that the corresponding wall of casing 54 can extend uniformly thereacross. In general, the arrangement of the permanent magnets relative to the frame assembly and electromagnet is such that a minimum of space is required, a feature which is particularly important when the invention is applied to extremely small, microminiature relays.

Though one particularly advantageous embodiment of the invention has been chosen for illustration, it wiil be understood that various changes and modifications therein can be made without departing from the scope of the invention as defined in the appended claims.

What is claimed is:

1. In an electromagnetic relay, the combination of a frame;

an electrom-agnet having a core, said core presenting a pole portion at each of its ends;

a first pole piece carried by said frame and magnetically coupled with one end of said core;

a second pole piece carried by said frame and magnetically coupled with the other end of said core;

a magnetic member carried by said frame at a point between said pole pieces and including first and sec ond portions disposed each on a different side of said electromagnet;

a first permanent magnet carried by said frame and extending beside said electromaguet between said first pole piece and said first portion of said magnetic member;

a second permanent magnet carried by said frame and extending beside said electromagnet between said second polepiece and said second portion of said magnetic member;

an elongated armature of magnetic material mounted for pivotal movement about an axis extending transversely of said electromagnet at the location of said magnetic member,

said first pole piece presenting a pole face directed toward one end portion of said armature and said second po le piece presenting a pole face directed toward the other end of said armature, said armature being mounted for pivotal actuation by said electromagnet selectively into engagement with said pole faces, engagment of said armature with the pole face of said first pole piece completing a path for flux from said first permanent magnet, such path including said first portion of said magnetic member; the portion of said armature extending from said pivotal ax-is toward said first pole piece, and said first pole piece, engagement of said armature with the pole face of said second pole piece completing a path for flux from said second permanent magnet, such path including said second portion of said magnetic member, the portion of said armature extending from said pivotal axis toward said second pole piece, and said second pole piece; and contact means selectively operated by said armature when the same is pivoted into engagement with said pole faces.

2. A relay in accordance with claim 1 and wherein each of said pole pieces includes a portion projecting transversely of the corresponding end of said core and exposed at one side of said electromagnet,

and each of said magnets are fiat bar magnets extending directly from the corresponding transversely projecting pol-e piece portion to the corresponding one of said first and second portions of said magnetic member.

3. A relay in accordance with claim 1 and wherein said magnetic member is U-shaped and disposed with its base extending adjacent to the adjacent face of said armature,

said first and second portions of said magnetic member constituting the legs of the U thereof.

4. A relay in accordance with claim 3 and wherein said magnets are flat bar magnets each having its outer face disposed in the same plane as the outer face of the corresponding one of the legs of said U-shaped magnetic member.

5. In an electromagnetic relay, the combination of a nonmagnetic frame member;

first and second pole pieces each including a pole face portion and a core-engaging portion projecting at right angles to said pole face portion,

said pole pieces being located at opposite ends of said frame member and said pole face portions extending toward each other along one face of said frame member and being fixedly secured to said frame member,

said core-engaging portions of said pole pieces both projecting from the same side of said frame member;

a generally U-shaped member of magnetic material located between the ends of said frame member with the base of the U extending across said one face of the frame member and the legs of the U extending in the same direction as do said core-engaging portions of said pole pieces;

an electromagnet including an elongated core extending parallel to said frame member and having its ends each engaged with a different one of said core-engaging portions of said pole pieces,

said legs of said U-shaped member being disposed each on a different side of said electromagnet; an armature of magnetic material mounted for pivotal movement about an axis extending across the base of said U-shaped member transversely of said electromagnet, the end portions of said armature each being disposed adjacent the pole face portion of a different one of said poie pieces, whereby pivotal movement of said armature resulting from energization of said electromagnet will bring one or the other of the end portions of said armature into engagement with the pole face portion of the corresponding one of said pole pieces;

a first permanent magnet extending along one side of said electromagnct between one of said core-engaging portions and one leg of said U-shaped member;

a second permanent magnet extending along the other side of said electromagnet between the other of said core-engaging portions and the other leg of said U- shaped member,

said permanent magnets being magnetically coupled to the respective ones of said core-engaging portions and said legs; and contact means selectively operated by said armature when the same is pivoted into engagement with said pole face portions. 6. A relay in accordance with claim 5 and wherein said electromagnet is enclosed in a nonmagnetic casing having fiat sides, and said permanent magnets and the legs of said U-shaped member extend along respective ones of said flat sides. I 7. In an electromagnetic relay of the type described, the combination of an electromagnet including an elongated core; two pole pieces each including a core-engaging portion; a magnetic member including a pair of leg portions spaced apart by a distance adequate to accommodate the transverse dimension of said electromagnet;

nonmagnetic frame means mounting said pole pieces in spaced relation with said core-engaging portions facing each other, said frame means also mounting said magnetic member between said pole pieces with each of said leg portions disposed in a common plane with an edge portion of a different one of said pole pieces,

said electromagnet being mounted with its core ends magnetically coupled to said core-engaging portions of respective ones of said pole pieces,

the body of said electromagnet being disposed between said leg portions of said magnetic member;

a first permanent magnet extending along one side of said electromagnet between one of said leg portions and the edge portion of the pole piece aligned therewith;

a second permanent magnet extending along the opposite side of said electromagnet between the other of said leg portions and the edge portion of the pole piece aligned therewith;

a magnetic armature mounted for pivotal movement about an axis which extends transversely of the electromagnet and is located adjacent to said magnetic member to receive flux from said permanent magnets via said magnetic member; and

contact means arranged to be actuated by pivotal movement of said armature.

8. In an electromagnetic relay of the type described,

the combination of an electromagnet including an elongated core and a nonmagnetic casing, the end portions of said core projecting through respective end walls of said casing, said casing having a pair of parallel, flat side walls;

a flat, nonmagnetic frame member extending beside said electromagnet, said parallel side walls of said casing being perpendicular to the plane of said frame member;

two pole pieces each including a flat core-engaging portion and a flat pole face portion at right angles to each other,

said core-engaging portions each extending adjacent a different end wall of said casing and being engaged with a different end of said core,

said pole face portions each overlapping a different end portion of said frame member and extending along the face of said frame member which is directed away from said electromagnet,

said pole face portions being secured to said frame member;

a U-shaped magnetic member,

the base of the U of said member extending transversely across said face of said frame member at a locationibetween the ends of said frame member,

the legs of the U of said member each projecting past said frame member along a different one of said parallel side walls of said casing;

a first permanent magnet extending along one of said parallel side walls between one of said legs and the core-engaging portion of one of said pole pieces;

a second permanent magnet extending along the other of said parallel side walls between the other of said legs and the core-engaging portion of the other of said pole pieces;

a magnetic armature mounted for pivotal movement about an axis parallel to and immediately adjacent the base of said magnetic member; and

contact means arranged to be actuated by pivotal movement of said armature.

9. In an electromagnetic relay of the type described,

the combination of an elongated electromagnet having a core;

a pair of pole pieces each disposed at a different end of said electromagnet and each magnetically coupled to a different end of said core;

a U-shaped magnetic member embracing said electromagnet intermediate the ends thereof;

a first permanent magnet extending along one side of said electromagnet between one of said pole pieces and one leg of said U-shaped member;

a second permanent magnet extending along the other 10 side of said electromagnet between the other of said pole pieces and the other leg of said U-shaped member;

a magnetic armature mounted for pivotal movement about an axis extending transversely of said electromagnet adjacent the base of said U-shaped member,

said armature extending generally lengthwise of said electromagnet and having its end portions each disposed for movement toward and away from a different one of said pole pieces when said armature is pivoted about said axis;

and contact means arranged for actuation by pivotal movement of said armature about said axis,

pivotal movement of said armature about said axis in one direction bringing one of said armature end portions into proximity with said one pole piece and providing a path for flux from said first permanent magnet, which path includes said U-shaped magnetic member, the corresponding half of said armature and said one pole piece,

pivotal movement of said armature in the opposite direction to bring the other of said armature end portions into proximity with said other pole piece providing a path for flux from said second permanent magnet, which path includes said U-shaped magnetic member, the corresponding half of said armature and said other pole piece,

at least one of said pole pieces being disposed for direct engagement by the corresponding one of said armature end portions.

10. In an electromagnetic relay of the type described,

the combination of a flat rectangular nonmagnetic frame member;

first and second pole pieces each secured to a different end of said frame member and each including a fiat portion projecting from said frame member at right angles thereto;

a U-shaped magnetic member having its base extending transversely across the face of said frame member which is directed away from said flat portions of said pole pieces, the legs of said U-shaped member projecting each from a different side of said frame member at right angles to the plane of said frame member;

a first fiat permanent bar magnet extending from the flat portion of said first pole piece to the corresponding leg of said U-shaped member;

a second fiat permanent bar magnet extending from the fiat portion of said second pole piece to the other leg of said U-shaped member,

said flat pole piece portions, said frame member,

the legs of said U-shaped member and said permanent magnets combining to partially define a rectangular enclosure;

an electromagnet including an elongated core,

said electromagnet being disposed within said enclosure with the ends of said core each magnetically coupled to the flat portion of a different one of said pole pieces;

a magnetic armature disposed on the side of said frame member opposite said electromagnet and mounted for pivotal movement about an axis extending transversely of said frame member at the base of said U-shaped member,

the end portions of said armature being arranged to engage the respective ones of said pole pieces upon appropriate pivotal movement of said armature about said axis, and

contact means disposed for actuation by such pivotal movement of said armature.

11. An electromagnetic relay in accordance with claim 10 and wherein said electromagnet is encased,

the casing of said electromagnet including end walls through which the respective end portions of said core project and parallel flat side walls,

1 1 said first permanent magnet and the associated one of the legs of said U-shaped member extending along one of said side walls and said second permanent magnet and the other leg of said U-shaped member extending along the other of said side walls.

12. In an electromagnetic relay, the combination of an elongated'electromagnet having a core;

first and second pole pieces each magnetically coupled to a different end of said core;

a magnetic member comprising a base portion, and a leg portion extending at right angles to said base portion;

nonmagnetic frame means mounting said magnetic member at a point intermediate the ends of said electromagnet,

I said base portion of said magnetic member extending transversely of said electromagnet, said leg portion of said magnetic member projecting beside said electromagnet and being spaced from said first pole piece;

a permanent magnet extending beside said electromagnet and having its ends magnetically coupled respectively to said first pole piece and said leg portion of said magnetic member;

an elongated armature of magnetic material mounted for pivotal movement about an axis extending transverselyof said electromagnet at the location of said base portion of said magnetic member,

said first pole piece presenting a pole face directed toward one end portion of said armature and said second pole piece presenting a pole face directed toward the other end portion of said armature,

said armature being mounted for pivotal actuation by said electromagnet selectively into engagement with said pole faces,

engagement of said one end portion of said armature with the pole face of said first pole piece completing a path for flux from said permanent magnehwhich path includes said magnetic member, the portion of said armature extending from said pivotal axis to said one end portion, and said first pole piece; and

contact means selectively operated by said armature when the same is pivoted into engagement with said pole faces.

13. In an electromagnetic relay, the combination of an elongated electromagnet having a core;

' two pole pieces each magnetic-ally coupled to a different end of said core;

a generally U-shaped magnetic member;

nonmagnetic frame means mounting said magnetic member intermediate the ends of said electromagnet with the base of the U of said member extending transversely of said electromagnet and the legs of the U of said member each projecting on a different side of said electromagnet;

an elongated armature of magnetic material mounted for pivotal movement about an axis extending trans versely of said electromagnet and located adjacent the base of the U of said magnetic member,

the base of the U of said magnetic member being located between said armature and said electromagnet,

said pole pieces each presenting a pole face and said pole faces being each directed toward a different end portion of said armature;

a plurality of flat permanent magnets each extending beside said electromagnet and each having its ends magnetically and fixedly coupled respectively to one of said pole pieces and one of the legs of said magnetic member,

pivotal movement of said armature into engagement with one of said pole faces completing a path for flux from at least one of said permanent magnets, which path includes said magnetic member, the corresponding half of said armature, and the one of said pole pieces presenting said one pole face,

completion of such flux path causing said armature to be latched magnetically to said one pole piece; and

contact means selectively operated by pivotal movement of said armature.

14. In an electromagnetic relay, the combination of an elongated electromagnet having a core;

two pole pieces each magnetically coupled to a different end of said core;

a generally U-shaped magnetic member including a base portion and two legs;

nonmagnetic means mounting said magnetic member intermediate the ends of said electromagnet with said base portion extending transversely of said electromagnet and said legs each projecting on a different side of said electromagnet, I

said base portion being substantially wider than said legs,

said legs each being offset from the center of said base portion toward a different end of said electromagnet, whereby each of said legs is closer to one of said pole pieces than to the other of said pole pieces;

a first permanent magnet extending beside said electromagnet and having its ends mechanically and magnetically coupled respectively to one of said pole pieces and the one of said legs most distant from said one pole piece;

a second permanent magnet extending beside said elcctromagnet and having its ends mechanically and magnetically coupled respectively to the other of said pole pieces and the other of said legs;

an elongated armature of magnetic material mounted for pivotal movement about an axis extending transversely of said electromagnet and located adjacent said base portion of said magnetic member,

said base portion being located between said armature and said electromagnet,

said pole pieces each presenting a pole face directed toward a different end portion of said armature,

pivotal movement of said armature into engagement with one of said pole faces completing a path for flux from the one of said permanent magnets coupled to the corresponding one of said pole pieces, such path including said magnetic member, the corresponding half of said armature, and said corresponding one of said pole pieces, completion of such path causing said armature to be latched magnetically to the one of said pole faces with which it is engaged; and

contact means selectively operated by pivotal movement of said armature.

15. In an electromagnetic rela, the combination of an elongated electromagnet having a core;

a fiat nonmagnetic frame member disposed beside said electromagnet and extending parallel thereto;

two pole pieces each magnetically coupled to a different end of said core and each presenting an exposed pole face directed in the same direction as the side of said frame member opposite said electromagnet;

a magnetic member located intermediate the ends of said electromagnet and including a portion extending across said side of said frame member,

said portion of said magnetic member being fixed to said frame member;

an elongated armature of magnetic material mounted for pivotal movement about an axis transverse to 13 said electromagnet and located at said portion of said magnetic member,

said frame member and said portion of said magnetic member being disposed between said armature and said electromagnet, pivotal movement of said armature in one direction about said axis bringing one end portion of said armature into engagement with one of said pole faces, pivotal movement of said armature in the other direction about said axis bringing the other end portion of said armature into engagement with the other of said pole faces; flat permanent magnet means extending between said pole pieces and said magnetic member and mechanically and magnetically coupied thereto, said permanent magnet means being at right angles to said frame member and extending beside said electromagnet, said permanent magnet means presenting like magnetic poles at both of said pole pieces,

engagement of said armature with either of said pole faces completing a path for flux from said permanent magnet means, which path includes said magnetic member, the corresponding half of said armature, and the one of said pole pieces engaged by said armature, completion of such flux path causing said armature to be latched magnetically to said one pole piece; and contact means selectively operated by pivotal movement of said armature.

References fiited in the file of this patent UNITED STATES PATENTS 15 2,941,130 Fischer et al June 14, 1960 2,955,174 Richert Oct. 4, 1960 2,960,583 Fisher et al Nov. 15, 1960 3,030,469 Lazich Apr. 17, 1962 3,067,305 Stout et a1 Dec. 4, 1962 

12. IN AN ELECTROMAGNETIC RELAY, THE COMBINATION OF AN ELONGATED ELECTROMAGNET HAVING A CORE; FIRST AND SECOND POLE PIECES EACH MAGNETICALLY COUPLED TO A DIFFERENT END OF SAID CORE; A MAGNETIC MEMBER COMPRISING A BASE PORTION, AND A LEG PORTION EXTENDING AT RIGHT ANGLES TO SAID BASE PORTION; NONMAGNETIC FRAME MEANS MOUNTING SAID MAGNETIC MEMBER AT A POINT INTERMEDIATE THE ENDS OF SAID ELECTROMAGNET, SAID BASE PORTION OF SAID MAGNETIC MEMBER EXTENDING TRANSVERSELY OF SAID ELECTROMAGNET, SAID LEG PORTION OF SAID MAGNETIC MEMBER PROJECTING BESIDE SAID ELECTROMAGNET AND BEING SPACED FROM SAID FIRST POLE PIECE; A PERMANENT MAGNET EXTENDING BESIDE SAID ELECTROMAGNET AND HAVING ITS ENDS MAGNETICALLY COUPLED RESPECTIVELY TO SAID FIRST POLE PIECE AND SAID LEG PORTION OF SAID MAGNETIC MEMBER; AN ELONGATED ARMATURE OF MAGNETIC MATERIAL MOUNTED FOR PIVOTAL MOVEMENT ABOUT AN AXIS EXTENDING TRANSVERSELY OF SAID ELECTROMAGNET AT THE LOCATION OF SAID BASE PORTION OF SAID MAGNETIC MEMBER, SAID FIRST POLE PIECE PRESENTING A POLE FACE DIRECTED TOWARD ONE END PORTION OF SAID ARMATURE AND SAID SECOND POLE PIECE PRESENTING A POLE FACE DIRECTED TOWARD THE OTHER END PORTION OF SAID ARMATURE, SAID ARMATURE BEING MOUNTED FOR PIVOTAL ACTUATION BY SAID ELECTROMAGNET SELECTIVELY INTO ENGAGEMENT WITH SAID POLE FACES, ENGAGEMENT OF SAID ONE END PORTION OF SAID ARMATURE WITH THE POLE FACE OF SAID FIRST POLE PIECE COMPLETING A PATH FOR FLUX FROM SAID PERMANENT MAGNET, WHICH PATH INCLUDES SAID MAGNETIC MEMBER, THE PORTION OF SAID ARMATURE EXTENDING FROM SAID PIVOTAL AXIS TO SAID ONE END PORTION, AND SAID FIRST POLE PIECE; AND CONTACT MEANS SELECTIVELY OPERATED BY SAID ARMATURE WHEN THE SAME IS PIVOTED INTO ENGAGEMENT WITH SAID POLE FACES. 